The present application claims priority to Korean Patent Application No. 10-2010-0124455 filed in the Republic of Korea on Dec. 7, 2010, the disclosures of which are incorporated herein by reference.
Generally, a light bulb has a short lifecycle, which may further shorten depending on its use time and therefore, may need to be periodically checked and exchanged, which will increase maintenance or exchange costs. However, an LED is advantageous in that it has a lower power consumption, semi-permanent lifecycle, rapid response rate, safety and environment-friendly property, in comparison to existing light sources such as fluorescent lights and incandescent lights. Therefore, many studies are being made to replace existing light sources with LEDs, which tend to substitute for general bulbs as a light source of a luminaire such as various kinds of indoor lamps, liquid crystal displays, electronic display boards, streetlamps or the like.
Since LED is generally weak against heat generated in operation, most LED luminaires use various methods for efficient heat dissipation. For example, Korean Unexamined Patent Publication No. 10-2009-0130473 discloses a power LED module for streetlamps, which emits heat through a heat dissipation plate or the like, and Korean Unexamined Patent Publication No. 10-2009-0095831 discloses a heat diffusion body having a heat diffusion fin or arranged doubly.
However, if natural cooling using a heat dissipation plate or a heat diffusion fin is applied, the heat dissipation efficiency deteriorates at an LED luminaire which is installed at the ceiling or in a narrow space. A method for emitting heat by forced cooling using a fan is also used in the art. However, this method requires a power source for driving the fan separately from the power source for the LED and consumes a lot of power.
Meanwhile, in the case a luminaire is installed at the ceiling or on a stand, a louver may be installed in order to limit a radiation angle of light emitted from the luminaire or prevent the light from causing dazzling to persons out of the radiation angle.
However, if the louver is used for the luminaire, the light blocked by the louver is wasted.